A signal indicator lamp disclosed in following patent literature 1 includes a cylindrical shape extending in a vertical direction and is configured by connecting indicator units and an acoustic notification unit. A circular opening part is formed at a side surface of a cylindrical case having an approximately cylindrical shape of the acoustic notification unit. A lid with a loudspeaker throat part is mounted to the opening part. The opening part includes a cylindrical part extending in a horizontal direction. A communicating hole is formed downward in the vertical direction at an upper part of an inner wall surface of the cylindrical part. A sound source setting part for storing and supporting a speaker and a mounting substrate of the speaker is integrally formed with an inner surface of the cylindrical case at an upper side of the communicating hole. Sound wave generated from the speaker is guided from the communicating hole and goes to a lower side in the loudspeaker throat part. Then, the sound wave is emitted in the horizontal direction from an acoustic radiating aperture of the loudspeaker throat part.